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Biomedical subjects

E M Bartels

Publications and source records attributed to E M Bartels.

At least 19 recordsLinked to original sources
PubMed2005

The uremic environment and muscle dysfunction in man and rat.

BACKGROUND: Patients reaching end-stage renal disease experience debilitating fatigue, with progression of this disease, rendering patients dysfunctional in their everyday lives. METHODS: In vivo measurements of muscle function, assessed using surface electromyography (EMG), were made on 25 patients prior to and after a session of hemodialysis (HD) treatment, along side in vitro measurements of muscle function in isolated rat muscles incubated in normal or uremic conditions approximating to those found in uremic rats (rat uremic: RU) or uremic humans (human uremic: HU). RESULTS: HD significantly affected plasma values, e.g. reducing urea (69%), creatinine (62%), potassium (23%) and phosphate (48%) concentrations in patients (all p < 0.01). Treatment also improved the EMG frequency of 2nd dorsal interosseous (fast-twitch) (p < 0.01), although no change was noted for vastus lateralis (slow-twitch). In isolated rat muscles, a uremic environment had no significant effect on slow-twitch soleus during field stimulation, however, in fast-twitch extensor digitorum longus, a significant 23% (RU) and 22% (HU) faster rate of decline in force was measured, compared to controls (p < 0.001 and p < 0.01, respectively). CONCLUSION: It is concluded that (1) muscle weakness and its electrophysiological correlates may be rapidly induced by uremic solutes and rapidly reversed when the solutes are removed by dialysis, and (2) fast-twitch muscles are more readily affected by uremic conditions than slow-twitch muscles.

Adult↗
PubMed2005

Learning effect of isokinetic measurements in healthy subjects, and reliability and comparability of Biodex and Lido dynamometers.

The aim of this study was to examine the learning effect during a set of isokinetic measurements, to evaluate the reliability of the Biodex System 3 PRO dynamometer, and to compare the Biodex System 3 PRO and the Lido Active dynamometers on both extension and flexion over the elbow and the knee at 60 degrees s(-1). Thirteen (nine women, four men) healthy participants were measured five times using the Biodex and once using the Lido dynamometer. The intervals between the first four tests were 20 min, and 1 week between tests 4 and 5. Between Biodex and Lido measurements there was a 20 min time interval. When comparing the first five measurements (Biodex), no systematic effect over time and an excellent reliability were found with respect to elbow and knee flexion and extension. No difference in muscle strength (Nm) between the Biodex and Lido was observed for knee flexion (P = 0.59), knee extension (P = 0.18) and elbow extension (P = 0.63). However, elbow flexion showed a 14.8% (95% CI: 11.2-18.4%; P = 0.0001) higher peak torque on Biodex. In conclusion, no learning effect was observed and the Biodex proved to be a highly reliable isokinetic dynamometer. A difference was observed when comparing Biodex and Lido on elbow flexion, but the difference did not outrange the expected variation found with a typical isokinetic measurement, which is why both sets of equipment seem applicable in clinical practice.

Adolescent↗
PubMed2005

Collagen structure in skin from fibromyalgia patients.

The distribution and amount of collagen in skin from a non-tender-point area from fibromyalgia patients was assessed by quantitative analysis of amino acids and by electron and light microscopy. Skin biopsies were obtained from the front of the thigh of 27 females who fulfilled the American College of Rheumatology criteria of fibromyalgia and from eight control subjects who were matched for gender, age and physical activity. Amino acids were determined by high-performance liquid chromatography. Electron and light microscopic investigations were carried out to examine tissue structure. Among the collagen-related amino acids, the mean number of hydroxyproline residues per 1,000 residues was 52.5 and 63.4 in fibromyalgia patients and control subjects, respectively (p = 0.050); proline residues were 81.7 and 110.0 (p = 0.006); and hydroxylysine residues were 14.7 and 10.1 (p = 0.002). The total amount of skin protein in proportion to dry tissue weight was 83.4% and 72.6% in fibromyalgia and controls, respectively (p = 0.037). The overall microscopic picture was normal. The lamellar structure of the perineurium and a deficiency in collagen packing in the endoneurium was observed more frequently and to a larger extent in fibromyalgia patients than in controls. In conclusion, there are some differences between the amino acid composition of skin proteins in fibromyalgia patients compared with controls. The amount of collagen may be lower in skin from fibromyalgia patients, and collagen packing in the endoneurium may be less dense.

Amino Acids↗
PubMed2004

Effects of antisecretory factor-derived peptides on contractions in guinea pig colon.

Two antisecretory factor (AF)-derived peptides have been studied in relation to effects on motility of guinea pig colon. Colon segments were isolated from adult guinea pigs and incubated in Tyrode Ringer. Motility was measured as the force and frequency of contractions upon addition of the derived peptides AF 1 (8 amino acids (aa)) and AF 3 (10 amino acids). At the lowest concentration (5 pM), peptide AF 1 induced a negative effect on the force of contraction in colon segments; an effect that was abolished by the cholinergic agonist carbachol. Peptide AF 3 induced a significant increase in the force of colon contractions at all concentrations (5-180 pM), with carbachol only reducing the effect of peptide AF 3 at a concentration of 15 pM. Both peptides increased contractile frequency, although the overall response was lower for peptide AF 3 than for peptide AF 1. It is concluded that antisecretory factor-derived peptides may play a role in regulating colon motility such that under pathophysiological conditions, they may serve to hasten the evacuation of noxious agents from the large intestine.

Animals↗
PubMed2003

Collagen and muscle pathology in fibromyalgia patients.

OBJECTIVE: To measure collagen concentration and search for muscle pathology in muscle non-tender-point areas from fibromyalgia (FM) patients. METHODS: Muscle biopsies were obtained from m. vastus lateralis of 27 carefully selected, female fibromyalgia patients, and from eight age-matched female control subjects. Amino acids were determined by HPLC and electron microscopy was performed. RESULTS: The FM patients had lower hydroxyproline and lower total concentration of the major amino acids of collagen than the controls. No significant difference was seen in the concentration of the major amino acids of myosin or of total protein. Electron microscopy showed no significant differences between FM patients and controls although atrophied muscle fibrils occurred in FM patients only, but frequencies were not significantly different. CONCLUSION: Fibromyalgia patients had a significantly lower amount of intramuscular collagen. This may lower the threshold for muscle micro-injury and thereby result in non-specific signs of muscle pathology.

Adult↗
PubMed2001

[Evidence-based grounds of physical therapy. Focus on training/exercise therapy of musculoskeletal problems].

Evidence of the benefit of exercise for patients with musculoskeletal problems was examined by analysing meta-analyses and systematic reviews. The literature search was confined to studies where pain and/or function was used as the outcome measure. Twenty-three meta-analyses/systematic reviews were covered, and the methodical quality was assessed. Nine out of twelve meta-analyses showed that exercise had a positive effect on groups groups diagnosed with intermittent claudication, fibromyalgia, incontinence, low back pain, and stroke, whereas one meta-analysis (exercise to prevent falls in the elderly) showed no effect. Of the systematic reviews, six out of 12 showed a positive effect and five were inconclusive, owing to the lack of clinical trials. We conclude that much more research in the field of exercise and physiotherapy is needed.

Evidence-Based Medicine↗
PubMed2001

[Pool exercise therapy of rheumatoid arthritis].

Aquatic therapy is a subgroup of balneotherapy and consists of exercises in a hot water pool. It uses the physical properties of water to achieve better mobility for patients whose pain, lack of muscle strength, and joint deformities are inhibiting factors when exercising on land. Pool therapy shows positive effects as part of the treatment of rheumatoid arthritis patients, but too few studies with an acceptable design and a well-defined patient group have been carried out. The documentation available on aquatic therapy indicates that more large clinical, controlled, and randomised studies must be conducted.

Arthritis, Rheumatoid↗
PubMed2001

A method to reduce the number of measured parameters when using isokinetic muscle strength as a clinical indicator in rheumatoid arthritis patients.

The aim of the study was to present a method enabling a reduction of the number of measurements when quantifying isokinetic muscle strength (IMS), and to describe an expression for IMS which is independent of measuring conditions. IMS is a measure of muscle strength used to categorise patients and to assess changes over time. IMS measurements involve one or several measures of peak torque at different chosen angular velocities. Comparisons between studies are difficult and an expression of IMS independent of measuring conditions is needed. Thirty-six women with rheumatoid arthritis were followed for 1 year. IMS was measured on five occasions on both knees at seven angular velocities, giving 10 sets of peak-torque data for each patient. The log[peak-torque]-angular-velocity diagram showed a linear relationship. From this, the peak-torque value at the chosen angular velocity of 30 degrees/s (IMS30) was estimated for each test and the uncertainties involved were quantified. IMS30 is a reliable parameter when comparing effort between knees, visits and patients, and may be based on three sets of data only. IMS may be expressed by a single value, IMS30, representing the fitted line in a log[peak-torque]-angular-velocity diagram. The regression line may be fitted by three or more angular velocities. In principle, IMS30 is independent of the chosen angular velocity, which makes it possible to use an estimated value as IMS30 to compare results, studies and centres in between.

Arthritis, Rheumatoid↗
PubMed2001

Use of isokinetic muscle strength as a measure of severity of rheumatoid arthritis: a comparison of this assessment method for RA with other assessment methods for the disease.

The aim of this study was to study the association between isokinetic muscle strength (IMS) and other clinical indicators of disability and disease activity in patients with rheumatoid arthritis (RA). A cohort of 36 RA patients was followed over a 1-year period with five measurements of disease activity at regular intervals during this time. IMS was measured at seven angular velocities in both knees, on five separate occasions. The measurement was expressed by the level of the fitted line of the seven peak torque values--IMS30. The association between IMS30 and clinical indicators was stated. As an indicator of disability the score from the Stanford Health Assessment Questionnaire (HAQ) was used. As indicators of disease activity morning stiffness, an index of swelling and pain in the joint, erythrocyte sedimentation rate (ESR) and haemoglobin (Hb) were chosen. Larsen's X-ray score was used as an indicator of bone destruction due to longer-lasting disease activity. IMS was significantly associated with the HAQ score, but not with indicators of disease activity or radiological findings. IMS was significantly associated with changes in indicators of disease activity, but not with the changes in the HAQ score, or in the X-ray-score. IMS showed the strongest association with changes in the degree of arthritis of the knee. In conclusion, IMS was associated with the HAQ score and can therefore be used when measuring outcome in a specific group of RA patients. Changes in IMS were associated with indicators of changes in disease activity, and are therefore usable as a measure of patient outcome. Of particular importance is that IMS decreased if a patient developed active arthritis in the knee, and normalised again when the inflammation decreased.

Adult↗
PubMed2000

MRI of the plantar structures of the foot after falanga torture.

Falanga is an ancient form of punishment or torture but is still commonly reported by our refugees. The late result of caning the heel and ball of the foot is a chronic painful condition with few clinical signs. The aim of the present study was to assess, by MRI, possible morphologic characteristics of the heel and ball of the foot, related to falanga and pain in correlation to clinical findings. Magnetic resonance imaging of the foot was obtained in 12 victims exposed to falanga torture and 9 healthy volunteers. Sagittal T1-weighted spin-echo images (TR 616-840 ms, TE 20 ms), T2-weighted spin-echo images (TR 1900 ms, TE 90 ms), and short tau inversion recovery (STIR) images (TR 1200 ms, TE 15 ms, TI 100 ms) were performed. The central portion of the plantar aponeurosis was generally significantly thicker in victims exposed to falanga torture as compared with that of controls (P < 0.05). In all except one of the victims, MRI demonstrated two layers of the thickened plantar aponeurosis: a deeper portion with normal homogeneous low signal intensity (SI) appearance, and a superficial layer with characteristic areas of mixed SI on both T1- and T2-weighted images. There were no signs of chronic muscular compartment syndromes, and the thickness of the plantar pad did not differ between the two groups. Magnetic resonance imaging may demonstrate morphologic characteristics of the plantar aponeurosis which may confirm falanga torture. Further imaging with more specific sequences is warranted to demonstrate the supposed injuries in the compartmental fat tissue chambers and the vascularity of the ball pad of the foot.

Adult↗
PubMed1998

Oxygen and lactate concentrations measured in vivo in the intervertebral discs of patients with scoliosis and back pain.

STUDY DESIGN: Oxygen concentrations in intervertebral discs were measured in 10 patients during discography and in 13 patients with scoliosis and 11 patients with back pain during spinal surgery. Lactate concentration profiles were measured in 12 of these discs. The discs were graded for degeneration by magnetic resonance imaging and histology where possible. OBJECTIVES: To determine if oxygen and lactate levels in human discs vary with degree of degeneration. Failure of nutrient transport is thought to lead to disc degeneration. SUMMARY OF BACKGROUND DATA: The disc is avascular. Oxygen is used by the disc cells, and lactate is produced. Low oxygen and high lactate concentrations have been measured in the center of healthy animal discs. METHODS: Oxygen concentrations were measured amprometrically. The sterilized gold-needle electrode was introduced into the disc during discography or after the disc was exposed surgically via an anterior approach. Concentration profiles of each disc took approximately 5 minutes to measure. Lactate concentrations were measured biochemically on the excised disc segment. RESULTS: Oxygen concentrations were highest at the disc surface and fell toward the center. Lactate concentrations showed the reverse profile. Oxygen levels were very variable, ranging from 5-150 mm Hg in the center of the nucleus. No correlation was seen with age, pathology, or degree of degeneration. Lactate concentrations ranged for the most part from 2 mmol/L to 6 mmol/L. CONCLUSIONS: Concentrations of metabolites depend on cellular activity and on transport of the metabolite between the blood supply and the cell. The correlation between degeneration and nutrition cannot be determined only from metabolite concentrations; measurements of metabolic activity and nutrient transport rates also are required.

Adolescent↗
PubMed1993

The myosin molecule--charge response to nucleotide binding.

A decrease in the net fixed electric charge in the A-bands of cross-striated muscle was observed by Bartels and Elliott [2,10] when the muscle went from the rigor to the relaxed condition. The current work localises the source of the charge decrease by following the net charge on myosin (in the form of concentrated gels) and also myosin rod and light meromyosin gels when the gels are exposed to different concentrations of ATP. The work includes a study of muscle A-bands when the muscle is exposed to the same variations in ATP concentrations as the protein gels. The work shows that (i) Only 100-200 microns ATP is needed to initiate the charge decrease between the rigor and relaxed conditions; (ii) the effect of ATP is seen in the muscle A-band and the myosin and myosin rod gels, but not in LMM gels; (iii) pyrophosphate (PPi) shows a similar charge effect to ATP. ADP does not affect the charge on myosin gels, on the other hand. The results suggest that the charge decrease caused by ATP or PPi is due to ligand interaction with one or more sites on the myosin molecule. This interaction causes a disseminated effect in the protein, and a consequent loss in net negative charge either by a decrease in the absorption, of anions to Saroff sites on the protein, or, less probably, by an increase in the absorption of cations at those sites.

Adenosine Diphosphate↗
PubMed1991

Single cell morphology of muscle in patients with chronic muscle pain.

In 119 patients referred with suspected fibromyalgia, biopsies from the quadriceps muscle were analyzed for "rubber band" morphology, and isokinetic quadriceps strength was measured. Eighty-four fulfilled the criteria for fibromyalgia, 26 had chronic myofascial pain (CMP) and 9 had other diseases including 5 with concomitant fibromyalgia. Twenty-four CMP patients and 48 fibromyalgia patients were randomly selected to match with regard to sex, age, smoking and drinking habits. "Rubber band" morphology was blindly graded on a biopsy score scale from 0 to 2. A statistically significant difference in biopsy score was found between the two matched groups (P = 0.003); median biopsy score in fibromyalgia was 0.42 and 0.25 in CMP. A cut-off value at 0.33 gave a specificity of 71% and a sensitivity of 63%. Isokinetic muscle strength did not differ in the fibromyalgia and CMP groups and was not related to the biopsy score. "Rubber band" morphology is seen more often in fibromyalgia patients than in CMP patients. The exact genesis of this phenomenon is still unknown but theories connected with the possible pathogenesis of the syndrome are presented.

Adult↗
PubMed1989

Patients with polymyositis show changes in muscle protein charges.

Polymyositis (PM) appears with indolent proximal muscle weakness and is an inflammatory disease with breakdown of muscle cells. In our study the protein charge concentrations of the contractile proteins in the A and I bands were determined, applying a microelectrode technique. Patients with PM show a lower protein charge concentration than healthy control subjects which may be caused by the breakdown and removal of the proteins in the contractile filaments. A tool to judge the state of the disease as well as an aid in diagnosis may have been found in this method.

Electrophysiology↗
PubMed1987

Diffuse X-ray scatter from myosin heads in oriented synthetic filaments.

X-ray results are presented concerning the structural state of myosin heads of synthetic filaments in threads. These were made from purified rabbit skeletal muscle myosin and studied by x-ray diffraction and electron microscopy by Cooke et al. (Cooke, P. H., E. M. Bartels, G. F. Elliott, and R. A. Hughes, 1987, Biophys. J., 51:947-957). X-ray patterns show a meridional peak at a spacing of 14.4 nm. We concentrate here on the only other feature of the axial pattern: this is a central region of diffuse scatter, which we find to be similar to that obtained from myosin heads in solution (Mendelson, R. A., K. M. Kretzschmar, 1980, Biochemistry, 19:4103-4108). This means that the myosin heads have very large random displacements in all directions from their average positions, and that they are practically randomly oriented. The myosin heads do not contribute to the 14.4-nm peak, which must come entirely from the backbone. Comparison with x-ray data from the unstriated Taenia coli muscle of the guinea pig indicates that in this muscle at least 75% of the diffuse scatter comes from disordered myosin heads. The results confirm that the diffuse scatter in x-ray patterns from specimens that contain myosin filaments can yield information about the structural behavior of the myosin heads.

Actin Cytoskeleton↗
PubMed1986

Histological abnormalities in muscle from patients with certain types of fibrositis.

In muscle biopsy specimens from fibrositis patients and healthy subjects no differences in electrical charges on the contractile proteins were detected with a microelectrode technique. However, microscopical examination of fibrositis muscle showed muscle fibres connected by a network of reticular or elastic fibres which are absent in normal muscle and which may be the cause of the disorder.

Adult↗